Suction box for a papermaking machine

ABSTRACT

A suction box formed from rigid front and back walls interconnected by a top and bottom set of spaced reinforcing members, a bottom wall interconnecting the front and backwalls and located between and spaced from said bottom and top reinforcing members and an outlet channel formed at at least one end of the box by an end wall of the box, the front and backwalls of the box and a downwardly extending wall projecting from the bottom wall thereby to form a substantially rigid suction box.

United States Patent Derrick R. Woodward Pointe Claire, Quebec;

Daniel Stucki, Lachine, Quebec, both of Canada Jan. 19, 1970 Dec. 21, 1971 JWl Ltd.

Montreal, Quebec, Canada Inventors Appl. No. Filed Patented Assignee SUCTION BOX FOR A PAPERMAKING MACHINE 10 Claims, 3 Drawing Figs.

U.S. Cl 162/363,

162/217 Int. Cl D21f l/52 Field of Search 162/21 1,

[56] References Cited UNITED STATES PATENTS 3,507,746 4/1970 Rhine 162/363 2,893,486 7/1959 Marti l62/374 X Primary Examiner-S. Leon Bashore Assistant Examiner-Alfred DAndrea, Jr. Attorney-Alan Swabey ABSTRACT: A suction box formed from rigid front and back walls interconnected by a top and bottom set of spaced reinforcing members, a bottom wall interconnecting the front and backwalls and located between and spaced from said bottom and top reinforcing members and an outlet channel formed at i at least one end of the box by an end wall of the box, the front and backwalls of the box and a downwardly extending wall projecting from the bottom wall thereby to form a substantially rigid suction box.

PATENTEB UEEZI 1971 INVENTORS Derrick R. WOODWARD Daniel STUCKI A TTORNEY BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to suction boxes. More specifically, the present invention relates to a boxlike construction to form a relatively rigid suction box having integral outlet channels directly connected to suitable sealing traps.

2. Description of Prior Art Section boxes form an essential part of a conventional fourdrinier papermaking machine. These boxes extend transversely between the upper and lower reach of the wire and draw water from the web forming on the wire to facilitate dewatering. Generally the boxes are positioned toward the couch end of the wire but in some cases may extend a substantial distance towards the breast roll. The location of the box between the breast roll and couch roll, the width of the machine and the type of stock being laid determine the amount of water that must be removed and thereby the size of outlet that must be provided.

As the width of paper machines has increased in the years, it has become more and more difficult to economically construct a suction box that will span the wire without unduly sagging along its length. Similarly, handling of the water withdrawn by the suction box can be a problem if conventional water-handling techniques wherein water is removed via drop legs at the back of the machine are used. More recently it has been proposed with machines incorporating save alls to empty the box into the save all using the liquid in the save all to form the water seal for the box. While this outlet arrangement alleviated, to some extent, the water load that must be carried in each box, it required that the down spouts be submerged in water in the save all to provide the seal, thereby requiring a certain minimum depth of water be maintained in the save all.

It has also been proposed to provide a suction box having an integral water seal extending the full length of the box, i.e., the full width of the machine. This system ensures substantially uniform dispensing of water from the box through the seal, but uses the bottom of the box as a reservoir in which water drawn from the web is maintained to the depth required (depending on the degree of vacuum in the box) to maintain the water seal. This arrangement inherently requires a relatively expensive construction in that the said depth of water extending uniformly across the box must be supported by the box and the structure of the box reinforced accordingly.

SUMMARY OF THE INVENTION seal.

Broadly, the present invention relates to a suction box having a rigid front and backwall, an upper and lower set of spaced reinforcing members interconnecting said front and backwalls, a bottom wall extending longitudinally of said front and back members spaced from said top and bottom reinforcing members and defining with said front and back walls the interior of the suction box, a pair of end walls closing the ends of said box and interconnecting said front and backwalls, an outlet channel at at least one end of said box, said channel being defined by said end wall, said front and backwalls, and a downwardly extending wall projecting from the bottom wall, a water seal formed by a turned up section extending from one of said end and downwardly extending walls and terminating in a lip, and a bottom edge of the other of said end and said downwardly walls, said edge being within said turned up section below said lip.

BRIEF DESCRIPTION OF DRAWINGS Further features, objects and advantages will be evident from the following detailed description of a preferred embodiment of the present invention taken in conjunction with the accompanying drawings in which:

FIG. 1 is a longitudinal section through a suction box constructed according to the present invention;

FIG. 2 is a section along the lines 2-2 of FIG. I; and

FIG. 3 is a section through a preferred construction of the front and backwalls to an enlarged scale relative to FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENTS The suction box 10 has substantially mirror image front and backwalls l2 and 14 respectively, end walls 16 (only one shown) and a bottom wall 18. The bottom wall 18 is spaced about one to two-thirds the distance between the top 20 and bottom 22 of the front and back walls 12 and 14 from the top 20. The spacing will vary depending on the amount of water to be carried which depends on the number of outlet channels and the structural requirements of the box.

The bottom wall 18 has a substantially flat central bottom section 24 bonded on its front and back sides by a pair of inclined sections 26 and 28 which direct water down toward the central section 24. These sections 24, 26 and 28 terminate at opposite ends of the box 10 in a downwardly extending wall 30 spaced from the end wall 16, This wall 30 in the illustrated arrangement extends from the front wall 12 to the backwall l4 and cooperates with the front and backwalls I2 and 14 and end wall 16 to provide an outlet channel 60 and a seal means as will be described hereinbelow.

Also extending between the front wall 12 and the backwall 14 adjacent the top edge of these walls is a plurality of spaced reinforcing members 32 which form an upper set of reinforcing members to support the cover of the suction box. These members 32, as illustrated, are substantially flat bars with sharpened upper edges 34 which support longitudinally extending rails 36 which in turn support wire supporting bars 38. The bars 38 are mounted on the rails 36 by means of a T connection generally indicated at 39 (see FIG. 2). The interconnections between transverse supporting members 32 and bottom 18 with the front and backwalls l2 and 14 provides a relatively high rigid box structure and a bottom wall structure that is well supported and easily able to carry the normal water load supply thereto.

To further increase the strength of the box, a bottom set of reinforcing members 52 formed by hollow triangular cross section bars arranged in spaced locations and extend between the walls 12 and 14 adjacent the bottom edges of these walls. The bars 52, the walls 12 and 14, and the bars 32 provide a boxlike structure that is exceptionally rigid.

The bottom wall 18 is also supported from the second set of bottom reinforcing bars 52 by a plurality of discrete plates 54 which extend across the bottom section 24 of the bottom wall 18.

The front and backwalls l2 and 14 are constructed substantially the same and therefore only one of these walls will be described in detail with reference to FIG. 3. Each of the walls 12 or 14 is formed by an inner sheet 40 which terminates at the top and bottom in outwardly extending flanges 42 and an outer sheet 44 which terminates at its top and bottom in inwardly extending flanges 46. The flanges 42 and 46 nest together as illustrated in FIG. 3 or may be arranged so that the flanges 42 are received between the flanges 46 or vice versa. A longitudinally extending reinforcing bar 48 is welded or otherwise secured to each of the flanges 42 and/or 46 to provide top and bottom reinforcement of the wall. A plurality of spaced longitudinally extending bars 50 (two illustrated) are secured to the inner sheet 40 to further reinforce same. These bars 50 bear directly against the inner surface of the outer sheet 44 and the outer sheet is fixed in position on the inner sheet, preferably by welding the flanges 46 to the flanges 42.

The rigid structure of the walls 12 and 14 coupled with the rigid bars 32 and 52 form, as above described, a substantially rigid rectangular boxlike structure encompassing the bottom wall 18 which is adequately supported by direct connection with the walls 12 and I4 and through plates 54 by the bars 52.

At each end of the box is an outlet channel 60 formed by the end wall 16, front and backwalls l2 and 14, and extensions thereof as indicated at 62 and 64, and downwardly extending outlet wall 30. In the illustrated arrangement, the wall 16 is extended to fonn an upturned section 66 which terminates in an outlet lip 68. The wall 30 terminates at its lower end in an edge 70 which is positioned within the upturned section 66 and below the lip 68 to provide a water seal in the outlet from the box. If desired, the arrangement may be reversed and the upturned section 66 and lip 69 project from the wall 30 and the wall 16 terminate in an edge 70. Generally, however, it is preferred to empty the box 10 into the save all (not shown) of the machine which is within the width of the wire so that the lip 68 preferably will be directed inwardly. As shown in dotted lines, the channel 60' formed by walls 80 and 82, one of which has an upturned section 66' and a lip 68' and the other which terminates in an end 70 may be provided at spaced locations along the box 10 to provide further outlets. There will normally be a channel 60 at each end of the box.

The channel arrangement at the ends of the box 10 provide a further boxlike reinforcing section formed by the walls defining the channel 60, i.e., the walls 30, l6, l2 and 14, thereby further adding to the rigidity of the suction box.

The suction box 10 is supported within the wire in a conventional manner on pedestals 84 and is connected with a suitable source of vacuum by vacuum connection 86. A conduit 88 having a bleed valve 90 is provided on the opposite end of the box to adjust the vacuum in the box. Preferably, a suitable gauge 92 will be provided to facilitate this adjustment.

In operation, a vacuum is maintained in the box 10 by withdrawing air through connection 86 whereby water is drawn from the stock travelling on the wire. This water flows along the bottom wall 18 to the nearest outlet channels 60 or 60' and builds up to the required depth in the channel 60 or 60' to a level L (see FIG. 1) equivalent to the amount of vacuum maintained in the box. The liquid level L at the outer lip 68 or 68' is above the edge 70 or 70' and thus provides a water seal for the box. Water spilling over the lip 68 or 68 is received in a suitable trough such as the save all of the machine and is conducted therefrom for further processing, if desired.

Modifications may be made without departing from the spirit if the invention in the appended claims.

We claim:

1. A suction box for a papermaking machine comprising rigid front and backwalls, a pair of end walls, a set of spaced bottom reinforcing members, each of said members intercon necting said front and backwalls, a bottom wall located between and spaced from said top and bottom reinforcing members and connected to said front and backwalls, an outlet channel at one end of said suction box, said channel being defined on one side by a downwardly extending wall connected to an end of said bottom wall and on another side by one of said end walls, one of said downwardly extending walls and said one of said end walls forming the channel terminating in an upwardly turned section which in turn terminates in an outlet lip below said bottom wall and the other of said downwardly extending wall and said one of said end walls forming the channel terminating in an edge located in said upwardly turned section below said lip, thereby to provide means for forming a water seal in said channel.

2. A suction box for a papermaking machine as defined in claim 1, wherein there is a second outlet channel at the othe end of said box.

3. A suction box for a papermaking machine as defined in claim 1, further comprising discrete plate means connecting each of said members of said set of bottom reinforcing members with said bottom wall.

4. A suction box for a papermaking machine as defined in claim 3, wherein said discrete plate means extends substantially perpendicular to said front and backwalls.

5. A suction box for a papermaking machine as defined in claim 1, wherein each of said front and backwalls is formed by a pair of spaced sheets with reinforcing members therebetween.

6. A suction box for a papermaking machine as defined in claim 4, wherein each of said front and backwalls is formed by a pair of spaced sheets with reinforcing means therebetween, each of said sheets having a laterally projecting flange and the flange of one of said sheets being received within and secured to the flanges of the other of said sheets, said reinforcing means extending longitudinally of said front and backwalls.

7. A suction box for a papermaking machine as defined in claim 2, wherein there are intermediate outlet channels formed by walls projecting downwardly from said bottom wall intermediate the ends of said suction box.

8. A suction box for a papermaking machine as defined in claim 1, wherein there are intermediate outlet channels formed by walls projecting downwardly from said bottom wall intermediate the ends of said suction box.

9. A suction box for a papermaking machine as defined in claim 4, wherein there are intermediate outlet channels formed by walls projecting downwardly for said bottom wall intennediate the ends of said suction box.

10. A suction box for a papermaking machine comprising rigid front and backwalls, a pair of end walls, a set of spaced top reinforcing members, each of said members interconnecting said front and backwalls, a bottom wall connected to said front and backwalls and spaced below said top reinforcing members but above the bottom of the end walls, an outlet channel at one end of said suction box, said channel being defined on one side by a downwardly extending wall connected to an end of said bottom wall and on another side by one of said end walls, one of said downwardly extending walls and said one of said end walls forming the channel terminating in an upwardly turned section which in turn terminates in an outlet lip below said bottom wall and the other of said downwardly extending wall and said one of said end walls forming the channel tenninating in an edge located in said upwardly turned section below said lip, thereby to provide means for forming a water seal in said channel.

t t l UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,629,058 Dated December 21, 1971 Inventor(s) Derrick R. Woodward et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In column 1, line 10, "Section" is to read --Suction--.

In column 3, line 46, after the phrase "a pair of end Walls" the phrase -a set of spaced top reinforcing members and-- must be included. V

Signed and sealed this 27th day of June 1972.

(SEAL) Attest:

EDWARDv M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-1050 (104 uscoMM-Dc B0376-P69 U.S GOVERNMENT PRINTING OFFICE: I969 0-366-334 

2. A suction box for a papermaking machine as defined in claim 1, wherein there is a second outlet channel at the other end of said box.
 3. A suction box for a papermaking machine as defined in claim 1, further comprising discrete plate means connecting each of said members of said set of bottom reinforcing members with said bottom wall.
 4. A suction box for a papermaking machine as defined in claim 3, wherein said discrete plate means extends substantially perpendicular to said front and backwalls.
 5. A suction box for a papermaking machine as defined in claim 1, wherein each of said front and backwalls is formed by a pair of spaced sheets with reinforcing members therebetween.
 6. A suction box for a papermaking machine as defined in claim 4, wherein each of said front and backwalls is formed by a pair of spaced sheets with reinforcing means therebetween, each of said sheets having a laterally projecting flange and the flange of one of said sheets being received within and secured to the flanges of the other of said sheets, said reinforcing means extending longitudinally of said front and backwalls.
 7. A suction box for a papermaking machine as defined in claim 2, wherein there are intermediate outlet channels formed by walls projecting downwardly from said bottom wall intermediate the ends of said suction box.
 8. A suction box for a papermaking machine as defined in claim 1, wherein there are intermediate outlet channels formed by walls projecting downwardly from said bottom wall intermediate the ends of said suction box.
 9. A suction box for a papermaking machine as defined in claim 4, wherein there are intermediate outlet channels formed by walls projecting downwardly for said bottom wall intermediate the ends of said suction box.
 10. A suction box for a papermaking machine comprising rigid front and backwalls, a pair of end walls, a set of spaced top reinforcing members, each of said members interconnecting said front and backwalls, a bottom wall connected to said front and backwalls and spaced below said top reinforcing members but above the bottom of the end walls, an outlet channel at one end of said suction box, said channel being defined on one side by a downwardly extending wall connected to an end of said bottom wall and on another side by one of said end walls, one of said downwardly extending walls and said one of said end walls forming the channel terminating in an upwardly turned section which in turn terminates in an outlet lip below said bottom wall and the other of said downwardly extending wall and said one of said end walls forming the channel terminating in an edge located in said upwardly turned section below said lip, thereby to provide means for forming a water seal in said channel. 